It is a tour de force of not only a huge widget library, but he explains how it is much more:

So what’s so smart about SmartGWT? Let me try to explain. SmartGWT is not just another Widget library. While most Ajax frameworks focus primarily on presentation and displaying mostly read-only data, either local or via XML / JSON, SmartClient was built with server side integration in mind. Most enterprise applications are not just about about data presentation, but about being able to propagate data changes made by the user to the backend. So while its tempting to use library X that has a cool tree widget, it’s not until you actually try to use it your application that you encounter the real world hard problems. For example, how do you take data from your business objects on the server to not only display in a tree widget, but also be able to update your data model when, say, the user reorders the tree nodes or make edits / deletes in the UI. How do you display hierarchical data where nodes may have hundreds of children? And so on..

Most Ajax frameworks stop short and leave it up to the user to manage state on the client side and propagating the changes to the server. This is not a trivial problem! Over the past few years UI widget libraries have improved significantly and there are now various options available to users. Simply put, having good looking widgets is not the hard problem today. In addition to having good looking widgets, having end-to-end integration of the UI components with the backend is the hard problem. It’s this 20% of the functionality that takes 80% of the time in building most enterprise applications.

The showcase will give you a good feel for what is out there, and it contains some interesting items including:

Miller Columns: The ColumnTree provides an alternate navigation paradigm for Tree data, sometimes called “Miller Columns” and seen in iTunes

Congratulations. I’ve been working with SmartGWT for the past 10 days or so and am amazed at the quality of the product. They have indeed thought about the real world problems when designing the library.

Very very slick indeed. I was very impressed when SmartClient was first featured on Ajaxian, so much so that I took it’s demo engine idea and wrote the Dojo Explorer (http://www.dojocampus.org/explorer). Anything that makes it simpler to integrate that excellent Ajax library with server side technologies can only be a good thing